Every communist nation that ever existed has built walls to keep their people from escaping. The need for these walls is because the people who are more productive know that they will be better off outside the walls rather than inside.
For the same reason, those who support socialism realize that no productive person who could, say, leave Kalifornia and move to Texas if the nation split up, would stay in Kalifornia. The socialists cannot afford to have the nation split up.
Many posters on this thread seem to be blind to what is happening in Greece and, more importantly, what is yet to happen.
There is simply not enough wealth in the world to do that which the socialists among us have promised to do. This reality is slowly being recognized.
Another poster on this thread points out that there is a limit to just how long productive people are going to be willing to be "fair" to those who expect themselves to be supported. I predict an UNCIVIL WAR.